Complete heart block and death following lamotrigine overdose

Context.?Lamotrigine is used for both seizure and psychiatric disorders. Overdoses typically follow a benign course. Case details.?A 19-year-old male with bipolar disorder ingested 4?g of lamotrigine. The patient suffered from multiple seizures, charcoal aspiration, respiratory arrest, prolongaton of the QRS interval on electrocardiogram, complete heart block, multiorgan failure and ultimately death. Discussion.?We describe the emergency department (ED) and ICU course for this patient and briefly review the toxic effects of lamotrigine and the pharmacokinetics with and without hemodialysis.     

Complete heart block in the pediatric patient.

Care for the pediatric patient with CHB focuses on signs and symptoms associated with respiratory failure and shock. Differences in size among pediatric patients--and in anatomy, physiology, and possible causes--should be considered. In children, cardiac arrest is usually secondary to respiratory arrest. Respiratory arrest should be anticipated in a pediatric patient with (1) decreased level of consciousness, (2) poor muscle tone, (3) increased respiratory rate or respiratory effort (nasal flaring, intercostal, subcostal, and suprasternal retractions); or (4) cyanosis. Shock is the failure of the cardiovascular system to perfuse vital organs adequately. Organ perfusion is determined by cardiac output, which in turn results from the heart rate times stroke volume. In CHB the slowing of heart rate can significantly decrease cardiac output, so the signs and symptoms of shock--especially level of consciousness, peripheral circulation, and blood pressure--must continually be reassessed.     

Complete heart block and death following lamotrigine overdose

CONTEXT.?Lamotrigine is used for both seizure and psychiatric disorders. Overdoses typically follow a benign course. CASE DETAILS.?A 19-year-old male with bipolar disorder ingested 4 g of lamotrigine. The patient suffered from multiple seizures, charcoal aspiration, respiratory arrest, prolongation of the QRS interval on electrocardiogram, complete heart block, multiorgan failure and ultimately death. DISCUSSION.?We describe the emergency department (ED) and ICU course for this patient and briefly review the toxic effects of lamotrigine and the pharmacokinetics with and without hemodialysis.     

Complete heart block and sudden death in mice overexpressing calreticulin

The expression of calreticulin, a Ca(2+)-binding chaperone of the endoplasmic reticulum, is elevated in the embryonic heart, and because of impaired cardiac development, knockout of the Calreticulin gene is lethal during embryogenesis. The elevated expression is downregulated after birth. Here we have investigated the physiological consequences of continued high expression of calreticulin in the postnatal heart, by producing transgenic mice that overexpress the protein in the heart. These transgenic animals exhibit decreased systolic function and inward I(Ca,L), low levels of connexin43 and connexin40, sinus bradycardia, and prolonged atrioventricular (AV) node conduction followed by complete heart block and sudden death. We conclude that postnatal downregulation of calreticulin is essential in the development of the cardiac conductive system, in particular in the sinus and AV nodes, when an inward Ca(2+) current is required for activation. This work identifies a novel pathway of events, leading to complete heart block and sudden cardiac death, which involves high expression of calreticulin in the heart.     

Complete heart block following penetrating chest trauma in operation Iraqi freedom

We present a 30-year-old US army soldier who had penetrating chest trauma from a road side explosive with focal cardiac injury. The soldier had penetration of his right atrium and subsequent traumatic membranous ventricular septal defect and complete heart block. He was brought to a Combat Support Hospital where fortuitously the assigned trauma surgeon on-call was a cardiothoracic surgeon, and the assigned trauma intensivist on-call was a cardiac electrophysiologist. Of course, the only source they knew of a pacemaker was halfway around the world. We discuss the management of this injury in an austere combat environment.     

Complete congenital heart block is associated with increased autoantibody titers against calreticulin

Complete congenital heart block (CCHB) is associated with anti-Ro/SS-A and anti-La/SS-B antibodies. Calreticulin, a calcium-binding, multifunctional protein of the endoplasmic reticulum with C-terminal KDEL-sequence, is not part of the Ro/SS-A ribonucleoprotein complex. In this study anti-calreticulin autoantibody responses in serum samples from 18 infants with CCHB, their mothers and in a control group of 11 anti-Ro/SS-A or anti-La/SS-B positive infants without heart block and their mothers were analysed. Specific enzyme-linked immunosorbent assays were performed. Nine out of 18 sera with CCHB contained IgG anti-calreticulin antibodies. Four sera of those with IgG antibodies also had IgM antibodies. One serum contained anti-calreticulin IgM antibodies only. In the non-CCHB group two sera were positive for IgG and one serum was positive for IgM anti-calreticulin antibodies. Sera of healthy infants were negative both for anti-IgG and anti-IgM calreticulin antibodies. Calreticulin is involved in calcium storage and therefore anti-calreticulin antibodies might influence the development of CCHB. The new finding of IgM autoantibodies and the observed differences in antibody response in infants and mothers support the hypothesis of a fetally mediated and passively acquired autoimmune disease.     

Complete heart block and cardiac tamponade secondary to Merkel cell carcinoma cardiac metastases

This is a unique case of Merkel cell carcinoma, a rare neuroendocrine tumor, metastasizing to the heart and inducing a progression of cardiac complications such as new-onset atrial fibrillation, malignant pericardial effusion with tamponade physiology, first-degree heart block, and complete heart block. Metastases to the heart are relatively rare but should be suspected if a patient with a known neoplasm presents with new cardiac manifestations. This is the first case report of cardiac metastases from Merkel cell carcinoma causing cardiac tamponade or complete heart block. This case highlights the clinical decision-making involved in managing cardiac tamponade and complete heart block in the setting of metastatic disease to the heart.     

Complete atrio-ventricular block after furosemide

We report a case of nonfatal complete atrio-ventricular (A-V) block after injection of 125 mg of furosemide by a central vena cava catheter. Accidents with this diuretic are very rare but this observation shows that it could induce A-V conduction disturbances. When large quantities of this diuretic must be used, we would recommend a slow injection rate to avoid such accidents.     

Vasospasm-induced heart block

A syncopal episode in an elderly patient with a history of carotid disease, multiple cardiac risk factors, and new onset chest pain presents diagnostic challenges. This case study describes the experience of a woman with coronary vasospasm accompanied by conduction deficits. The patient's history, diagnostic work-up, and treatment program are presented. The relationship between the coronary artery anatomic defects and the conduction abnormalities are discussed.     

Complete atrioventricular block induced by alcohol abuse

A patient with a history of chronic alcoholism and a reversible complete AV block due to excessive alcohol abuse is reported. The conduction disorder gradually improved after the complete cessation of alcohol consumption as the only means of therapy. During 6 month follow-up he continued to abstain from alcohol and had intact AV conduction.     

Congenital complete heart block

Recent studies have demonstrated immunologic abnormalities in the mothers of infants with congenital complete heart block. The disorder should be suspected when a slow pulse rate is detected before or after birth. The block most often occurs in the AV node. There are several specific indications for pacemaker therapy. Most patients who survive beyond infancy are able to lead relatively normal lives.     

Dobutamine-induced complete heart block

Dobutamine is commonly administered as a pharmacologic stressor in patients with limitations precluding exercise testing. The case report presented is one of transient complete heart block resulting from dobutamine sestamibi stress testing. Shortly after initiating the dobutamine infusion, the patient became pale and presyncopal, with hypotension and a heart rate of 50 beats per minute. Subsequently, third-degree heart block developed which lasted transiently and resolved. Subsequent cardiac evaluation of the patient revealed no cardiac etiology for her symptoms. Though bradycardia is infrequently noted in patients receiving dobutamine during stress electrocardiogram, complete heart block is a possibility during dobutamine-induced stress echocardiography and must be recognized as a potential risk.